Almost all living creatures including plants are formed of cellular tissues. In virtually every living being these cellular communities form an outer protective barrier of tissues. In mammals this protective barrier is commonly referred to as skin. Similarly in vegetables and plants the outer shell is really a protective barrier of skin or a peel that grows as the vegetable or fruit matures providing a shield from intrusions to the underlying and generally more vulnerable inner tissue. For example in citrus fruits the juicy high liquid content of these tissues would be impossible to mature without the protective outer peel.
Accordingly the use of such natural shields or barriers to protect more vulnerable cells or tissue is the norm.
It is therefore of little surprise that on the molecular level bacteria whether aerobic or anaerobic have generally been known to exhibit an outer protective cellular membrane similar to a skin and any treatment to destroy such a bacteria typically required weakening or penetrating this outer membrane. Once penetration occurred the viability of the organism was diminished resulting in a cessation of viability.
Bacteria while being a relatively lower order entity has nonetheless a very strong and evolutionary desire to survive and thus is one of the more adaptive organisms found on earth. Mutant strains of bacteria are commonly feared because of their huge capacity to adapt to threats particularly those involving the use of microbial disinfectants and antibiotics used to fight disease.
Microorganisms grow through a form of cellular division. Blood agar cultures are used to grow colonies of bacteria. The cluster starts out invisible to the naked eye and within 24 to 48 hours can be a large colony of millions of bacteria. This has always been a well known phenomenon of bacterial growth.
Now, however, this colony building technique has been adapted to form multi-layered barrier structures and shields similar to a skin. This protective barrier building is now referred to as biofilms.
In U.S. Pat. No. 6,726,898 entitled “Local delivery of agents for disruption and inhibition of bacterial biofilm for treatment of periodontal disease” the inventors refer to the work of J. W. Costerton et al, Microbial biofilms, Annu. Rev. Microbial 49:711 (1995) wherein they recite:                Recent attention has been given to removing unwanted biofilms forming in various industrial processes. Biofilms are notoriously resistant to removal. The tendency of bacteria to adhere, secrete an adhesive extra cellular matrix and grow is a strong evolutionary advantage difficult to overcome. So far, little success has been realized. Observation of living bacterial biofilms by modern methods has established that these microbial populations form a very complicated structural architecture. See, e.g., J. W. Costerton, et al., Microbial biofilms, Annu. Rev. Microbial, 49:711 (1995). This suggested the operation of a cell—cell signaling mechanism for bacteria to produce these complex structures. After twenty years of research, it is generally assumed now that all enteric bacteria and gram negative bacteria are capable of cell density regulation using acylated homoserine lactones (AHLs) as autoinducer molecules.        In early stages a biofilm is comprised of a cell layer attached to a surface. The cells grow and divide, forming a dense mat numerous layers thick. When sufficient numbers of bacteria are present (quorum) they signal each other to reorganize forming an array of pillars and irregular surface structures, all connected by convoluted channels that deliver food and remove waste. The biofilm produces a glycocalyx matrix shielding them from the environment. Urinary tract and urinary catheter infections are examples of biofilm infections.        As the biofilm matures, the bacteria become greatly more resistant to antibiotics than when in the planktonic (free cell) state. See H. Anwar, et al, Establishment of aging biofilms: a possible mechanism of bacterial resistance to antimicrobial therapy, Antimicrob Agents Chemother 36:1347 (1992). The host immune system is also significantly less effective against bacteria in the biofilm state. See E. T. Jensen, et al, Human polymorphonuclear leukocyte response to Pseudomonas aeruginosa biofilms, Infect Immun 5:2383 (1990). Certain bacterial strains may be able to confer resistance protecting the biofilm from host defense components that would otherwise bind to the surface of viable bacteria and kill them.        
In U.S. Pat. No. 6,777,223 entitled “Methods for eliminating the formation of biofilm”, the inventors describe biofilms as:                biological films that develop and persist at the surfaces of biotic or abiotic objects in aqueous environments from the adsorption of microbial cells onto the solid surfaces. This adsorption can provide a competitive advantage for the microorganisms since they can reproduce, are accessible to a wider variety of nutrients and oxygen conditions, are not washed away, and are less sensitive to antimicrobial agents. The formation of the biofilm is also accompanied by the production of exo-polymeric materials (polysaccharides, polyuronic acids, alginates, glycoproteins, and proteins) which together with the cells form thick layers of differentiated structures separated by water-filled spaces. The resident microorganisms may be individual species of microbial cells or mixed communities of microbial cells, which may include aerobic and anaerobic bacteria, algae, protozoa, and fungi. Thus, the biofilm is a complex assembly of living microorganisms embedded in an organic structure composed of one or more matrix polymers which are secreted by the resident microorganisms.        
This prior art invention related to methods for preventing or removing biofilm on a surface, comprising contacting the surface with an effective amount of a composition comprising one or more acylases and a carrier to degrade a lactone produced by one or more microorganisms, wherein the degradation of the lactone prevents or removes the biofilm.
Similarly U.S. Pat. No. 6,875,422 suggests the use of one or more of an oral bacterial flora controlling agent as a treatment for biofilms found in the periodontal pocket.
Almost all of the prior art literature on the subject of eliminating or preventing biofilms suggests one or more drugs or chemical agents as the solution to this problem as well as well known cleaning procedures such as debridement in the practice of periodontal treatments.
What is sorely lacking is a safe and reliable method to break down the cellular barrier properties of these complex architectural microbial structures called biofilms.
It is therefore an object of the present invention to provide such a method to reduce or eradicate microbial biofilms not only on surfaces, but within tissues and organs.